Marjory Stoneman Douglas student David Hogg is among those calling for a nationwide student walkout to protest gun violence on Friday, April 20. But he’s also standing in support of Columbine High School students who won’t be walking out Friday, the 19th anniversary of the Columbine massacre.

On April 11, Hogg re-tweeted a call for a walkout on the anniversary of the Columbine shooting. The walkout is in part a voter registration drive for young people.

The #NationalSchoolWalkout;

•April 20th

•10am

•Walkout of school, university, work, home because gun violence happens everywhere and effects everyone.

Save the future, be the change, walkouthttps://t.co/gZofbs4L0Z

— National School Walkout (@schoolwalkoutUS) April 10, 2018

When you guys walk out on 4/20 if you want to register people to vote or have someone register people to vote be outside your school go to https://t.co/sYUm0L2ST3 please do this I think we can all agree young Americans should vote more but they can’t unless they #RegisterToVote

— David Hogg 🟧 (@davidhogg111) April 11, 2018

However, Columbine High School has historically had a different approach to its tragic anniversary. The school is closed on April 20 so that students can participate in community service projects.

Hogg got the message.

https://twitter.com/davidhogg111/status/985830979582484480